Cellulose aerogels are the latest generation of aerogels and have also received extensive attention due to their renewable and biocompatible properties. Herein, cellulose aerogel was facilely prepared by using NaOH/urea solution as solvent, raising the temperature to control gelation and drying wet gel sequentially. With NaOH/urea solution as solvent, the cellulose concentration has an important impact on the micromorphology of cellulose aerogels, while the aging time rarely affects the micromorphology. The appropriate solvent and drying method allow the formation of different cellulose crystalline structures. Different from the Cellulose Ⅰ crystalline structure of raw cellulose powder, the cellulose phase of as-prepared cellulose aerogels belongs to the Cellulose Ⅱ crystalline structure, and to some extent the pyrolysis temperature is also lower than that of raw cellulose powder. The resultant cellulose aerogel prepared by using NaOH/urea solution as solvent and freeze-drying has a uniform macroporous structure with a macropore size of 1~3 µm.
Keywords: cellulose aerogels; micromorphology; sol-gel method; temperature control.